The A't'trr are an advanced alien hive mind from Eur'uui Universe. The A't'trr are actually thousands of microscopic creatures impossible to see with the naked eye. Collectively they flourish in ultraviolet light; revealing electric blue tendrils wherever they have spread. When feeding, they glow. The A't'trr feed on heat and oxygen. They can withstand extreme temperatures such as direct exposure to a blow torch, or the heat of an explosion. They claim that an explosion that would destroy the SGC would be enough to allow them to spread across the planet.